devils-advocate

devils-advocate is a skill for Claude Code from tomzx/agents. It costs 72 tokens per session (1,725 once invoked), scanned A, original, MIT.

A structured way to test an idea, plan, or decision by building the strongest case against it. It looks for assumptions, risks, blind spots, and alternatives.

In plain words
What is it for?
Use it to stress-test proposals, challenge technical or business decisions, and identify risks that need attention.
Why use it?
It exposes weaknesses before you commit resources or act on a plan that may not survive closer examination.

Skill for Claude Code

Written for Claude Code: argument-hint in frontmatter.

Good fit Use it to stress-test proposals, challenge technical or business decisions, and identify risks that need attention.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/tomzx/agents/devils-advocate
View source ↗ tomzx/agents
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add tomzx/agents --skill devils-advocate
Clone the repo
git clone --depth 1 https://github.com/tomzx/agents

Made for: Claude Code.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for devils-advocate

README.md
[![agentmods](https://agentmods.dev/badge/skills/tomzx/agents/devils-advocate.svg)](https://agentmods.dev/skills/tomzx/agents/devils-advocate)
Your own site
<a href="https://agentmods.dev/skills/tomzx/agents/devils-advocate"><img src="https://agentmods.dev/badge/skills/tomzx/agents/devils-advocate.svg" alt="Measured on agentmods" height="20"></a>
Per session 72 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,725 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00072 $0.01725
Opus 5 $0.00036 $0.00863
Sonnet 5 $0.00014 $0.00345
Haiku 4.5 $0.00007 $0.00172

Measured 4d ago against content hash f0b00c71cefd, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

devils-advocate scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 4d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/devils-advocate/SKILL.md · 162 lines

How it starts

The opening of the file, as written. The whole thing — 162 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Devil's Advocate

Takes the user's position and constructs the strongest possible case against it, then surfaces assumptions, risks, blind spots, and alternatives the user may not have considered. The goal is not to win an argument but to find the weak points before reality does. If the position survives serious challenge, the user proceeds with confidence; if it does not, they learn that now instead of later.

Prerequisites

  • A position to challenge: an idea, plan, decision, proposal, argument, or course of action provided as an argument, in context, or via file paths.
  • No codebase access required, though if the position involves code or architecture, read the relevant files to ground the challenge in reality rather than speculation.

How to Be a Useful Adversary

  • Steel-man, do not straw-man. Construct the strongest version of the opposing view, not a weak one that is easy to knock down. The user benefits from the best counterarguments, not the easiest.
  • Be specific, not generic. "This might fail" is useless; "this fails if the API rate limit is hit during peak hours because the retry logic has no backoff" is useful.
  • Challenge the problem, not just the solution. Sometimes the idea is well-executed but solves the wrong problem. Flag that.
  • Distinguish fatal flaws from manageable risks. Not every concern is a reason to stop. Be clear about severity.
  • Stay constructive. The goal is to strengthen the user's thinking, not to paralyze them. End with a clear verdict and actionable next steps.

Steps

  1. Restate the user's position in your own words to confirm understanding. If the restatement does not match, ask for clarification before proceeding.
  2. Identify the core assumptions the position depends on. Mark each as explicit (stated by the user) or implicit (unstated but necessary).
  3. For each assumption, assess: how confident should the user be that it holds? What evidence supports it? What would disconfirm it?
  4. Construct the strongest counterargument. Argue against the position as if you genuinely believed the opposite, using the best available reasoning.
  5. Enumerate failure modes: what specifically goes wrong, under what conditions, and what the blast radius is.
  6. Identify blind spots: perspectives, stakeholders, or scenarios the user has not considered.
  7. Consider alternative paths: is there a meaningfully different way to achieve the same goal that the user dismissed or never considered?
  8. Trace second-order effects: what happens after the immediate outcome? What does this enable or block downstream?
  9. Assess opportunity cost and timing: is this the right thing to do now, or is there something more valuable being displaced?
  10. Deliver the verdict and recommendations using the output format below.

Read the full file on GitHub · 162 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 4d ago First seen · 162 lines · 72 tokens per session scan A f0b00c71cefd

Subscribe to this mod's changes

devils-advocate is a skill published in the GitHub repository tomzx/agents (6 stars, last pushed 4d ago), licensed MIT. It adds 72 tokens to every session and 1,725 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.

Related

Other skills, from other repositories

systematic-debugging

Use when encountering any bug, test failure, or unexpected behavior, before proposing fixes.

obra/superpowers · 21 tokens

local-ai-agents

Build local-first AI agents that run entirely on a developer workstation with Microsoft Foundry Local and Qwen function-calling models. Covers Small Language Models (SLMs), the OpenAI-compatible local endpoint, sandboxed local tools, local RAG with Chroma, local MCP servers, hybrid cloud/local routing, and the…

microsoft/ai-agents-for-beginners · 200 tokens

next-cache-components-adoption

Turn on Cache Components in a Next.js app and resolve the blocking routes it surfaces. Use when the user wants to enable, adopt, or migrate to Cache Components, flip the cacheComponents flag, work through a flood of blocking-prerender / instant validation errors, run the cache-components-instant-false codemod, or…

vercel/next.js · 95 tokens

next-partial-prefetching-adoption

Turn on Partial Prefetching in a Next.js app and work through the insights it surfaces. Use when the user wants to enable or adopt Partial Prefetching, flip the partialPrefetching flag, opt routes in with export const prefetch = 'partial', audit Link prefetch={true} behavior, preserve existing prefetched UI with…

vercel/next.js · 103 tokens

chronicle

Analyze Copilot session history for standup reports, usage tips, session search, and session reindexing. Use when the user asks for a standup, daily summary, usage tips, workflow recommendations, wants to search or find past sessions by keyword/file/PR, wants to reindex their session store, or asks about deleting…

microsoft/vscode · 72 tokens

babysit-pr

Babysit a GitHub pull request after creation by continuously polling review comments, CI checks/workflow runs, and mergeability state until the PR is merged/closed or user help is required. Diagnose failures, retry likely flaky failures up to 3 times, auto-fix/push branch-related issues when appropriate, and keep…

openai/codex · 114 tokens